The Penrose Virtual Directory Project has released Penrose 0.9.7 on safehaus (penrose.safehaus.org). Penrose is a server for a directory protocol such as LDAP, but unlike a traditional directory server, does not master the data itself in its own database. Instead a virtual directory will dynamically translate requests it receives to operations in other protocols or data models, such as to a relational database.

Highlights include:
Query optimizer.
Compatibility with Java 1.5.
Various bug fixes and performance enhancements.

You can find more information in the release notes.